for A, B being AltCatStr holds
( A,B have_the_same_composition iff for a1, a2, a3, x being object st x in dom ( the Comp of A . [a1,a2,a3]) & x in dom ( the Comp of B . [a1,a2,a3]) holds
( the Comp of A . [a1,a2,a3]) . x = ( the Comp of B . [a1,a2,a3]) . x )